Spring 2019 New Professors Lecture

Materials Chemistry & Nanophotonics: Towards Next-Generation Bioprobes and Energy Converters

By Eva Hemmer, Assistant Professor, Department of Chemistry and Biomolecular Sciences

Abstract: Based on their outstanding optical and magnetic properties, rare earth-based compounds have been suggested for a wide range of applications including the fields of biomedicine, optoelectronics, and solar energy conversion. For instance, the capability of rare earth-based materials to emit visible and near-infrared (NIR) light under NIR excitation is highly sought after when aiming for biomedical applications. This is as NIR light penetrates deeper into biological tissue and is less phototoxic than UV light commonly used for optical bioprobes. Our favorite nanomaterials are rare earth-based fluorides (MREF4, M = alkali metal, RE = rare earth), and our research addresses challenges in their synthesis as well as the establishment of structure-property relationships. This is crucial for the understanding of fundamental physico-chemical processes in such materials and needed for the design of next-generation bioprobes and energy converters. This presentation will shine a light on the versatile landscape of rare earth-based materials focusing on materials synthesis and rare earth-specific optical as well as magnetic features.

Biography: Eva Hemmer received her PhD in materials science from Saarland University (Germany, 2008), where she focused on the synthesis of rare earth alkoxides and their decomposition to rare earth-containing inorganic nanomaterials. This experience was further deepened during her postdoctoral studies, working on rare earth-based near-infrared bioimaging at the Tokyo University of Science (2009-2012). In 2013 she was awarded a Feodor Lynen Research Postdoctoral Fellowship from the Alexander von Humboldt Foundation to join the groups of Profs. Fiorenzo Vetrone and Francois Légaré at INRS-EMT (Université du Québec, Canada, 2012-2015) to develop nanothermometers based on upconverting nanoparticles. In winter 2016, Eva came to Ottawa in order to design and study novel multifunctional rare earth-based nanocarriers for biomedical and energy conversion applications at the Department of Chemistry and Biomolecular Sciences.

Ultrafast THz spectroscopy – timing is everything

By Jean-Michel Ménard, Assistant Professor, Department of Physics

Abstract: The far-infrared region of the electromagnetic spectrum (wavelengths in the range between 10 µm and 1 mm), also known as the terahertz (THz) frequency band, is one of the richest areas of research and development. It encompasses the rotational spectra of molecules, the vibrational spectra of solids, plasmonic resonances in semiconductors and electrical transitions of multiple quasi-particles such as excitons. Time-resolved THz spectroscopy is an emerging characterization technique for solids, liquids and gases that relies on the generation and detection of broadband phase-locked optical pulses in the far-infrared region. This technique allows experimentalists to trace the oscillating electric field of light, hence providing both amplitude and phase information about an optical pulse transmitted through an optical medium. For example, one can extract the complex dielectric function of this medium and precisely determine both its refractive index and absorption spectrum. Most importantly, time-resolved THz spectroscopy is an ultrafast technique that can characterize a sample at an exact time. Then, by taking multiple successive measurements, one can effectively reconstruct a movie of the complex inner dynamics inside the material with a frame duration approaching the femtosecond. This feature allows experimentalists to explore a variety of ultrafast transient states in materials and explore their fascinating new properties. In this talk, I will present intriguing quantum states than can be investigated, and potentially controlled, with THz light.  I will also discuss innovations in THz photonics recently developed by our group to acquire privileged information on quantum systems by gaining access to a larger spectral bandwidth and achieving higher detection sensitivity.

Biography: Jean-Michel Ménard is Assistant Professor and principal investigator of the ultrafast terahertz spectroscopy lab at the University of Ottawa. He completed his PhD in 2010 under the guidance of Henry van Driel at the University of Toronto. He was then awarded a Humboldt Fellowship to investigate ultrafast dynamics with terahertz spectroscopy in the lab of Rupert Huber at the University of Regensburg. In 2014, he joined the Russell Division at the Max Planck Institute for the Science of light in Erlangen as a postdoctoral researcher and moved back to Canada in January 2016 to start his own research program combining his expertise in optics and materials physics. He is a member of the Max Planck-uOttawa Centre for extreme and quantum photonics.  His research interests include time-resolved terahertz spectroscopy of quantum materials and the development of photonics tools based on nonlinear optical propagation in hollow-core photonic crystal fibers.

Epigenetic determinants of metabolic phenotypes in fish

By Jan Mennigen, Assistant Professor, Department of Biology

Jan Mennigen

Abstract: The Mennigen lab is focused on the comparative physiology of metabolism in the diverse class of teleost fish. Using an integrative approach spanning molecular, cellular and organism level approaches, we seek to determine how environmental factors, both natural and anthropogenic in nature affect teleost metabolism across their life-cycle and between generations. A recent focus that exemplifies this approach is the study of molecular epigenetic mechanisms, especially the posttranscriptional regulation of gene expression by small non-coding RNA molecules termed microRNAs. Taking advantage of the zebrafish and rainbow trout models, our lab is interested not only in delineate the epigenetic regulation of metabolism in the largest and diverse vertebrate infraclass, but also in insights generated from these studies towards two translational axes, sustainable aquaculture and environmental and human health.

Biography: Jan obtained his PhD in the Trudeau and Moon labs at the University of Ottawa, where he used largely gene expression-based approaches to determine metabolic and reproductive consequences in fish exposed to endocrine disrupting aquatic contaminants. He then undertook two post-doctoral appointments, first, as a European Marie-Sklodowska-Curie fellow (2011-2013) at the Institut National de la Recherche Agronomique in France, where he investigated the regulation and function of hepatic microRNAs in hepatic glucose and lipid metabolisms in rainbow trout with Drs. Skiba-Cassy and Panserat. Afterwards, he went to the University of Texas at Austin in the US, where he investigated developmental and transgenerational effects of persistant organic pollutants on metabolic and reproductive physiology in the rat. Jan joined the Department of Biology in July 2016 as Assistant Professor in Comparative physiology.

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